The post shows how to generate an oriented bounding box based on the three axis known in advance. The 3D model is displayed by a CUModel object. We will calculate the two farthest points, positive farthest point and negative farthest point along the special direction. Then generate a polydata from Read more…
As we know, we can create a linear transform to change model to the special orientation and position. Refer to The Releationship Between Local Transform And Pose Transform. Let’s define orientation and position by three axis and point. , , and origin = . The matrix for the linear transform Read more…
Here is a example that vtkTransform object failed to deep copy the other one. #include <iostream> #include <vtkSmartPointer.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkTransform.h> #define vtkSPtr vtkSmartPointer #define vtkSPtrNew(Var, Type) vtkSPtr<Type> Var = vtkSPtr<Type>::New(); int main() { setbuf( stdout, nullptr ); vtkSPtrNew( trans, vtkTransform ); auto matrix = trans->GetMatrix(); matrix->SetElement( Read more…
You can use the key ‘i’ to enable or disable the vtkSliderWidget object defaultly. Here is a post about how to use vtkSliderWidget to control other model, Control The Size Of Model By VtkSliderWidget. But we don’t want the shortcut key to influence the program UI sometimes. So let’s forbid Read more…
Original Status The initial scene looks like the following image. I will rotate cone around point (1, 0, 0) and direction (0, 0, 1). Code #include <vtkActor.h> #include <vtkCleanPolyData.h> #include <vtkDistancePolyDataFilter.h> #include <vtkNamedColors.h> #include <vtkNew.h> #include <vtkPointData.h> #include <vtkPolyDataMapper.h> #include <vtkPolyDataReader.h> #include <vtkProperty.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkRenderer.h> #include Read more…
The article shows how to create a simple vtk render window project and show it in the web browser. We need emscripten tool and the visualization toolkit installed. emscripten : https://emscripten.org/docs/getting_started/downloads.html VTK: https://vtk.org/ Build the VTK source to get JS library before our coding. This example uses C plus plus Read more…
I found a bug when we do matrix inverse calculation by vtkTransform object. The version 8.2.0 and 9.1.0 of VTK has the same potential risk in vtkMatrix4x4::Invert(const double inElements[16], double outElements[16]).Let’s see the source code, it judges whether the determinant value is zero by ==. The equal comparison operation for Read more…
We had used vtkImplicitPolyDataDistance to calculate the distance from a point to the target points set in the post Calculate Distance From A Point To PolyData In VTK. We will try a new way using KD-Tree to find the closest point to the test point. The following example puts a Read more…
We had introduced a way to keep a few special models awalys on the top layer in 3D scene. The relative post: https://www.weiy.city/2020/03/make-model-always-on-top/. But it will fail to shift polygons, lines, and points sometimes, eg. when we are in the WebAssembly environment (wasm) for web page.Let’s use an another method Read more…